applies element default before resolving element properties

samples/point.html

@@ -139,7 +139,6 @@
 									yValue: 0,
 									backgroundColor: 'rgba(101, 33, 171, 0.5)',
 									borderColor: 'rgb(101, 33, 171)',
-									borderWidth: 15,
 									radius: 50,
 									click(context) {
 										console.log('Annotation', context);

src/annotation.js

@@ -135,10 +135,10 @@ function updateElements(chart, state, options, mode) {
     if (!el || !(el instanceof elType)) {
       el = elements[i] = new elType();
     }
-    const properties = el.resolveElementProperties(chart, annotation);
-    properties.options = merge(Object.create(null), [elType.defaults, annotation]);
+    const mergedOptions = merge(Object.create(null), [elType.defaults, annotation]);
+    const properties = el.resolveElementProperties(chart, mergedOptions);
+    properties.options = mergedOptions;
     animations.update(el, properties);
-
     el._display = isAnnotationVisible(chart, annotation, el);
   }
 }

test/specs/point.spec.js

@@ -96,4 +96,67 @@ describe('Point annotation', function() {
 
     });
   });
+
+  describe('applying defaults', function() {
+
+    it('should not throw any exception', function() {
+      function createAndUpdateChart() {
+        const config = {
+          type: 'scatter',
+          options: {
+            animation: false,
+            scales: {
+              x: {
+                display: false,
+                min: 0,
+                max: 10
+              },
+              y: {
+                display: false,
+                min: 0,
+                max: 10
+              }
+            },
+            plugins: {
+              legend: false,
+              annotation: {
+                annotations: {
+                  point: {
+                    type: 'point',
+                    borderWidth: 5,
+                    display(context) {
+                      if (context.element) {
+                        context.chart.annotationRadius1 = context.element.options.radius;
+                      }
+                      return true;
+                    },
+                  },
+                  point2: {
+                    type: 'point',
+                    xScaleID: 'x',
+                    yScaleID: 'y',
+                    xValue: 8,
+                    yValue: 8,
+                    borderWidth: 0,
+                    display(context) {
+                      if (context.element) {
+                        context.chart.annotationRadius2 = context.element.options.radius;
+                      }
+                      return true;
+                    },
+                  }
+                }
+              }
+            }
+          },
+        };
+
+        var chart = acquireChart(config);
+        if (isNaN(chart.annotationRadius1) || isNaN(chart.annotationRadius2)) {
+          throw new Error('Defaults radius is not applied to annotaions : 1-' + chart.annotationRadius1 + ', 2-' + chart.annotationRadius2);
+        }
+      }
+      expect(createAndUpdateChart).not.toThrow();
+    });
+  });
 });